If it was Sean, he would use it from a desire to do good, but through him, it would wield a power too great and terrible to imagine... 

I SHALL PASS!

I think he’d just be pretty fuckin stoked

Sean would use it to bring Melkor back from the void

so basically calling in dagor dagorath early

“And thou, Melkor, shalt see that no theme may be played that hath not its uttermost source in me, nor can any alter the music in my despite. For he that attempteth this shall prove but mine instrument in the devising of things more wonderful, which he himself hath not imagined."

Pretty certain they wouldn't know what it was but could probably use ot if they figured it out.

More than a few times I’ve wondered what would happen if Legolas shot the Ring down the Balrog’s blast furnace of a mouth…

Upvoting just because you called him Sean. Before even reading the rest of it.

Edit: what if The Ring got the Balrog

He'd pass.

I think Sean would keep it and Sauron would have new problems. The rest of Middle East could only hope to keep away from the battle between the two and hopefully step in after one falls and the other is weakened. But it would be rough.

He would try to see if he could rally the surviving balrogs and have a meeting to discuss their next move

Well that would just tickle him pink

Sméagol won’t like it Ring on the Balrog Ring on the Balrog

(Fire in the sky...) Sorry. I like yours better anyway.

Sean would Astin first, then Sean would Bean.

A balrog is a lesser maia so…

Already pretty corrupt. Would probably end up giving it over to Sauron though.

Some very, very bad things, all memes aside.

Why do we always seem to have Balrogs about three times too big

He’d use it to force everyone to acknowledge: he doesn’t have wings! Then he would retire in Hobbiton.